How to Grow Green Onions Using Hydroponics

by Ruth de Jauregui

Green onions are grown from green onion varieties or harvested as the immature spouts of larger onion varieties.

Providing fresh salads for your family is easy when you begin hydroponic gardening. Lettuce greens, tomatoes and peppers are among the vegetables grown in hydroponic systems. However, small root vegetables such as beets, carrots and green onions are also easy to grow hydroponically. With a waterproof container, a piece of polystyrene, 4-inch pots and a soilless growing medium, you can grow green onions in your kitchen window, or on a larger scale on your sun porch or patio.

1

Select a container for the hydroponic reservoir. For example, a simple plastic storage bin or a plastic-lined planter box are suitable options, as long as they are waterproof and at least 6 inches deep. Place the reservoir in a sheltered location that receives eight to 10 hours of sunlight daily.

2

Cut a piece of 2-inch thick polystyrene foam to fit just inside of the reservoir. Allow 1/4- to 1/2-inch clearance around the perimeter of the foam, as it will float on top of the hydroponic solution.

3

Mark a 6-inch grid onto the top of the foam with a pencil and yardstick. Cut holes through the foam with the 3 1/2-inch hole saw, centered at each intersection of the grid.

4

Insert a 4-inch plastic flowerpot into each hole in the foam. Fill the pots with a planting medium such as perlite, rockwool or coconut coir.

5

Space four onion sets equidistant apart in each pot. Cover with 1 inch of planting medium.

6

Mix the hydroponic fertilizer with water in the reservoir, according to the manufacturer's directions. Fill the reservoir within 3 inches of the top edge.

7

Place the foam float on the top of the fertilizer solution. Add more water or fertilizer as needed to maintain the liquid in the hydroponic system.

8

Monitor the hydroponic garden for pests and weeds. While indoor hydroponic gardens rarely have pest problems, occasionally pests and weeds from outdoors make their way into the sun porch or grow room.

9

Harvest the green onions in three to four weeks. Replant each pot immediately after harvesting to ensure a continuous supply of green onions.

Things You Will Need

Large waterproof container

Polystyrene, 2 inches thick

Carving knife

Yardstick

Electric drill with 3 1/2-inch hole saw

Plastic flowerpots, 4-inch round

Perlite, rockwool or coconut coir

Onion sets

Measuring cups

Hydroponic fertilizer

Tips

Green onions are grown as an annual vegetable crop across the United States.

Start onion seeds in damp paper towels, then pick out with tweezers and gently insert into the planting medium.

Stagger the planting dates to maintain a regular supply of green onions for your kitchen.

Replace the hydroponic solution every four to six weeks. Pour the used solution into your flowerbeds or vegetable garden.

Warnings

Wear gloves, a dust mask and safety glasses to protect your skin, lungs and eyes when cutting the foam and mixing the hydroponic solution.

Keep children and pets away from your hydroponic garden; it is an extreme drowning hazard.

About the Author

Ruth de Jauregui is the author of "The Soul of California—Cooking for the Holidays," "Ghost Towns" and "100 Medical Milestones That Shaped World History." A old-school graphic artist and now a writer, she worked in the Napa Valley as a catering assistant and has 30 years experience in gardening and home improvement.

Photo Credits

Have Feedback?

Thank you for providing feedback to our Editorial staff on this article. Please fill in the following information so we can alert the Home Guides editorial team about a factual or typographical error in this story. All Fields are required.